Photographic material with improved properties

ABSTRACT

A photographic material is provided having a layer support backed on both sides with polyolefine and having at least one layer of a light sensitive silver halide gelatine emulsion layer thereon. The rear surface of the support having thereon a water impermeable layer containing a major proportion of a water insoluble binder and minor proportions of an antistatic agent and an inorganic or organic matting agent.

Uited States Patent Vet-burg Oct. 30, 1973 [54] PHOTOGRAPH: MATERIALWITH 3,399,995 9/1968 Winchell 96/87 A KMPROVED E'ROPERTIES FOREIGNPATENTS OR APPLICATIONS Inventor: Werner g, Carl-Rumpff, 815,662 7/1959Great Britain 96/87 A Germany [73] Assignee: AGFA-GevaertAktiengesellschaft, Primary Exami"e" Rnald Smith Leverkusen GermanyAttorney-Walter C. Kehm, Samson B. Leavitt and Morton Friedman [22]Filed: Feb. 11, 1971 [21] Appl. No.: 114,666 [57] ABSTRACT Aphotographic material is provided having a layer 52 us. c1. 96/85, 96/87A pp backed on both Sides with Polyolefine and [51] 03 1 32 having atleast one layer of a light sensitive silver ha- [58] Field of Search96/87 A, 85 gelatine emulsion layer thereon- The rear Surface of thesupport having thereon a water impermeable [56] References Cited layercontaininga major proportion of a water insolu- UNTED STATES PATENTS blebinder and minor proportions of an antistatic 3 525 621 8/1970 M11 9 A Xagent and an inorganic or organic matting agent.

1 er 2,725,297 11/1955 Morey 96/87 A 7 Claims, No Drawings PHOTOGRAPHICMATERIAL WITH IMPROVED PROPERTIES The invention relates to aphotographic material having a polyolefme backed layer support the rearsurface of which carries an antistatic layer and which is easier towrite on.

It is known to use polyolefine backed sheets, especially polyolefinebacked paper, as layer supports for photographicmaterials which containlight sensitive silver halide emulsion layers. The main advantage ofthese polyolefine backed materials over simple supports such as paperalone is that they absorb much less of the aqueous photographic baths inthe course of processing so that both the amount of chemicals used andthe treatment time are reduced. Polyolefine backed supports, andespecially supports which are backed with polyethylene have, however,certain disadvantages, the main disadvantages being that they becomeelectrically charged much more readily and that the rear surface of thesupport is much more difficult to write on than paper supports. Toovercome these disadvantages, polyethylene backed paper used forphotographic purposes is treated with antistatic layers and withauxiliary layers which are intended to improve the writing surface. Theknown methods used for improving the tendency of these layer supportsnot to become charged have, however, not provided satisfactory results.This is mainly due to the fact that the choice of antistatic agentswhich are photographically inert is relatively small. Thus there are nosufficiently effective antistatic agents which can be incorporated intothe polyethylene layer without exerting an adverse effect on thephotographic layers. Other antistatic agents which are compatible withsilver halide emulsion layers, however, are washed out to a considerableextent in the course of processing so that the antistatic effect isseverely reduced in the processed material. For this reason, attemptshave also been made to arrange the antistatic layer between the supportand the polyethylene layer, but the effect of layers arranged in thisway is generally not sufficient.

lt is among the objects of the invention to modify polyolefme backedsupports for-photographic materials so that their tendency to becomeelectrostatically charged will be reduced and at the same time theirquality as a writing surface will be improved.

A photographic material comprising a layer support which is backed withpolyolefine on both sides and comprising at least one light sensitivesilver halide gelatine emulsion layer has now been found in which awater impermeable layer is applied to the rear surface of the layersupport in a thickness of 0.5 to ID microns, which water-impermeablelayer contains at least 70 percent by weight of a water-insolublebinder, 5 to 25 percent by weight of an antistatic agent and l topercent by weight of an inorganic or organic matting agent, based on thetotal weight of the dry layer.

Suitable binders for the back'coating in the material according to theinvention are water-insoluble synthetic polymers or copolymers.Copolymers which contain (l) a polymerizable olefine in particularethylene, (2) a half-ester of an a, B-unsaturated carboxylic acid inwhich the alcohol component is preferably aliphatic or cycloaliphaticand contains up 'to eight carbon atoms, preferably a maleic acidhalf-ester, (3) vinyl chloride and (4) a vinyl ester of a saturatedcarboxylic acid, preferably of an aliphatic carboxylic acid containingup to five carbon atoms have been found to be particularly suitable. Theproportion of the components in the copolymer may vary within widelimits. Copolymers of the following composition are especiallyadvantageous:

9 30 percent weight of a polymerizable olefine in particular ethylene 212 percent by weight of a half-ester of dicarboxylic acid and 58 percentby weight of a mixture of vinyl chloride and the vinyl ester in whichthe proportion of the vinyl ester is 15 to 45 percent by weight of themixture.

' The copolymers used according to the invention preferably have anaverage molecular weight of between 20,000 and 100,000. They should befree from low molecular weight constituents. They are particularly easyto use in the form of an aqueous dispersion. The polymer latices have aparticle size of less than 0.5 microns.

The matting agents may be either organic or inorganic substances.Suitable organic substances are e.g., polyacrylonitrile dispersions;these must be heterogeneously dispersed in the layer. Inorganic mattingagents are especially suitable, e.g., silicic acid or silicates andespecially aluminium oxides, if desired in the form of theiroxihydrates.

Suitable polyolefine backed supportsare e.g., those which containpolyethylene or polypropylene layers. Polyethylene backed paper ispreferred.

In principle, a wide variety of antistatic agents may be used for thelayers in the material according to the invention. The choice ofasuitable antistatic agent will depend on-the properties required of thelayer. according to the invention. Thefirst requirement, of course, isthat the antistatic agents should be photographically inert so that theywill not have an adverse effect on the light sensitive photographiclayers with which they come into contact. Polystyrene sulphonic acid andits derivatives have been found to be especially useful for thispurpose. Suitable products of this type have been described in GermanPat. No. 912,778. Spirocyclic .organic phosphoric acid esters are alsoquite suitable, e.g., those mentioned in U.S. Pat. No. 3,428,456.

An excellent antistatic effect and an excellent writing surface at theback of the photographic material are achieved with the layers accordingto the invention. The material according to the invention fully meetsthe requirements in practice as regards both these properties. Theantistatic properties and hence the surface resistance of the materialare adequately preserved even after the photographic processing.

At the same time, the rear surface can be easily and clearly imprintedwith the usual printing dyes such as those used in stamping pads or inautomatic printing mechanisms in photographic processing apparatus orthe dyes used in typewriter ribbons or with ordinary pencils. Thewriting produced on these surfaces is resistant to the photographicbaths and is still clearly legible after the photographic process. Thisis very important when automatic apparatus is used for processingbecause in that case information is written on the back of the exposedphotographic material to note the filter values in the case of colourphotographic copies or reference numbers or other data of the client.

The rear coating layers according to the invention are applied bytheusual methods of dipping, spraying or wiper application. A preliminarytreatment such as exposure to corona discharge according to DeutscheAuslegeschrift No. 1,159,159 isadvisable to obtain better bonding ofthese coatings. The coatings are advantageously produced by mixingaqueous solutions or dispersions of the components and applying them tothe polyoleiine backed material from the aqueous medium. After the rearcoating according to the invention has been applied, the light sensitivephotographic silver halide emulsion layers and auxiliary layers may beapplied to the other side of the layer support.

The rear coating is suitable both for black and white materials and forcolour photographic materials and especially for the latter.

The properties of the photographic layer are not disadvantageouslyaffected by the rear coating.

The binder for the rear coatings may, of course, consist of a mixture ofvarious polymers. According to one advantageous embodiment, the layermay contain ionic polyurethanes in addition to the copolymers mentionedabove, especially anionic polyurethanes of the type described in US.Pat. No. 3,297,989. Small quantities of hydrophilic binders such asgelatine may also be added to the layers.- When using the copolymermentioned above which has been described in Belgian Pat. No. 741,338 upto 30% by weight of other binders, based on the total weight of binder,may be used, such as the anionic polyurethanes mentioned above orgelatine.

Example 1 A rear coating of the following casting solution is applied toa layer support of paper which has been backed on both sides withpolyethylene:

1 liter of a percent aqueous solution of polystyrene sulphonic acid(molecular weight 40,000, sulphonic acid group content 50 to 80 percentbased on 1 mol of styrene); I

liter of a 50 percent polymer latex of a copolymer having the followingcomposition:

18.2 percent by weight of vinyl acetate 63.2 percent by weight of vinylchloride 15.3 percent by weight oflethylene and 3.3 percent by weight ofthe cyclohexyl half-ester of maleic acid, and i 10 g ofa commercialaluminium silicate, e.g., the aluminium silicate sold by FarbenfabrikenBayer AG. under the name Baysikal.

The rear coating is applied with a conventional roller applicator. Thethickness of the dried layer is 2 microns.

A bonding layer is first applied to the other side of the layer supportto improve the bond between the polyethylene and the hydrophilicphotographic layers, and this is then coated with an ordinary silverhalide gelatine emulsion layer used for black and white copyingmaterial.

The photographic material is exposed and figures and letters are thenwritten on the back with the usual instrument using a typewritingribbon. The material is then developed, fixed and dried in known manner.

After the photographic processing, the letters and numerals are clearlylegible.

Measurements of the conductivity of the rear coating before and afterprocessing indicate that the conductivity is sufficiently high toprevent troublesome accumucourse of the process. The surface resistanceof the unconverted polyethylene layer is 10 ohm.

EXAMPLE 2 A rear coating of the following casting solution is applied toa layer support which has been backed with polyethylene on both sides:

1 liter of a 10 percent aqueous. solution of polystyrene sulphonic acid(molecular weight 40,000 to 80,000, sulphonic acid group content 50 topercent based on 1 mol of styrene),

0.8 liter ofa 50 percent aqueous latex of the following copolymer:

32.6 percent by weight of vinyl acetate 47.5 percent by weight of vinylchloride 14.0 percent of ethylene 5.5 percent by weight of thecyclohexyl half-ester of maleic acid Latex solids content: 59 percent,

0.2 liter of a 30 percent aqueous dispersion of an anionic polyurethaneaccording to US. Pat. No. 3,428,456 (the polyurethane is a poly-additionproduct of 218.5 g of the polyester of adipic acid, hexanediol andneopentyl glycol (OH number 63), 32.6 g of hexane-1,6-diisocyanate and46 g of a 20 percent aqueous solution of sodium aminoethane sulphonate,and

8 g of aluminium hydroxide.

The layer has a thickness of 3 microns when dry. A layer of thiscomposition has practically the same good qualities when applied to asupport which has been coated with polypropylene.

The usual layers for a multilayered colour photographic material areapplied to the other side of the layer support. These layers comprise ablue sensitive silver halide emulsion. layer which contains yellowcoupler, a yellow filter layer, a green sensitive silver halide emulsionlayer containing a magenta coupler and a red sensitive silver halideemulsion layer containing a cyan coupler.

The layers are processed as indicated in Example 1.

Before processing, the rear coating has a surface resistance of 10 ohmand after processing a surface resistance of 10 ohm. The rear coating isa good writing surface. The writing on it is resistant to the processingbaths.

Similar advantages are obtained with rear coatings applied from castingsolutions of the following composition:

1.2 liter of a 10 percent polystyrene sulfonic acid solution 0.9 literof the copolymer latex of Example 1 0.3 liter of the polyurethanedispersion of Example 2 5 g of aluminium hydroxide 5 g of aluminiumsilicate 0.2 of saponin as wetting agent in the form of a 5 percentaqueous solution. 2.

Same composition as above, but instead of aluminium hydroxide/aluminiumsilicate mentioned there as matting agent, 0.01 of a 12 percent aqueousdispersion of polyacrylonitrile (molecular weight about 100,000) isused.

I claim:

1. A photographic material comprising a layer support which is backedwith polyolefine on both sides and at least one light sensitive silverhalide gelatine emulsion layer, characterised in that a waterimpermeable layer having a thickness of 0.5 to microns is applied to therear surface of the layer support, said layer containing at least 70percent by weight of a waterinsoluble binder, said binder comprising acopolymer of ethylene, a half-ester of an a,B-unsaturated carboxylicacid, vinyl chloride and a vinyl ester of a saturated carboxylic acid, 5to 25 percent by weight of an antistatic agent and l to 10 percent byweight of an inorganic or organic matting agent, based on the totalweight of the dry layer.

2. A photograhic material according to claim 1, characterised in that itcontains, as the layer support, paper which has been backed withpolyethylene on both sides.

3. A photographic material according to claim 1, characterised in thatthe binder has the following composition:

9 to 30 percent by weight of ethylene 2 to 12 percent by weight of ahalf-ester of the dicarboxylic acid to 58 percent by weight of a mixtureof vinyl chloride and the vinyl ester, the proportion of the latterbeing 15 to 45 percent by weight of this mixture.

4. A photographic material according to claim 1, wherein the mattingagent is an insoluble inorganic aluminum compound.

5. A photographic materialaccording to claim 4, wherein the matting.agent is aluminum hydroxide or aluminum silicate.

6. A photographic material according to claim 1, wherein the antistaticagent is polystyrene sulphonic acid.

7. A photographic material as defined in claim 1 wherein said half-esterof an a,,B-unsaturated carboxylic acid is the cyclohexyl half-ester ofmaleic acid and wherein said vinyl ester of a saturated carboxylic acidis vinyl acetate.

2. A photograhic material according to claim 1, characterised in that itcontains, as the layer support, paper which has been backed withpolyethylene on both sides.
 3. A photographic material according toclaim 1, characterised in that the binder has the following composition:9 to 30 percent by weight of ethylene 2 to 12 percent by weight of ahalf-ester of the dicarboxylic acid 90 to 58 percent by weight of amixture of vinyl chloride and the vinyl ester, the proportion of thElatter being 15 to 45 percent by weight of this mixture.
 4. Aphotographic material according to claim 1, wherein the matting agent isan insoluble inorganic aluminum compound.
 5. A photographic materialaccording to claim 4, wherein the matting agent is aluminum hydroxide oraluminum silicate.
 6. A photographic material according to claim 1,wherein the antistatic agent is polystyrene sulphonic acid.
 7. Aphotographic material as defined in claim 1 wherein said half-ester ofan Alpha , Beta -unsaturated carboxylic acid is the cyclohexylhalf-ester of maleic acid and wherein said vinyl ester of a saturatedcarboxylic acid is vinyl acetate.